Mississippi authorities have launched a homicide investigation into the death of a 19-year-old woman who was doused with a flammable liquid and set on fire.

Panola County Coroner Gracie Gulledge says the cause of death was thermal injuries. Gulledge was hoping to final autopsy results late Tuesday. Authorities say initial autopsy results reveal Chambers died from burns that covered 98 percent of her body.

District Attorney John Champion says investigators were questioning several possible witnesses and reviewing Chambers' cellphone data.

A passerby called firefighters who found her body Saturday near her burning car near Courtland.

Darby says detectives were working to learn who the woman may have been with before her death.